How Is 0 not positive?

Maybe it was! https://github.com/kevva/is-positive/commit/3db0639fb52c463f...

"0 is neither positive nor negative." https://en.wikipedia.org/wiki/0_%28number%29#Mathematics

Actually there is a positive 0 and a negative 0 in JavaScript. Try 1/+0 and 1/-0 in your browser console and notice how the result is different for each (+Infinity and -Infinity respectively).